There’s one thing that major oil companies can’t get enough of these days–unconventional gas.

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A BP oil refinery

Virtually every deal that big oil has cut in recent months focused on resources of this type. ExxonMobil agreed in December to pay around $30 billion for XTO Energy, which specializes in extracting gas trapped in shale rock in the U.S. France’s Total agreed in January to acquire a quarter of Chesapeake Energy‘s huge shale gas resource in Texas for $2.25 billion. Last week, BP cut a much smaller deal with Lewis Energy for half of its Texas shale territory.